The fintech innovator is a small-cap company -- for now.After some rough years following the early days of the pandemic, Upstart (UPST +5.62%) has regained its momentum in a big way. The company is expecting to report its first billion-dollar revenue year ever in 2025, and growth has been impressive throughout the business.However, Upstart is still a relatively small company with a market cap of about $4.5 billion. The stock is about 88% below its all-time high, and the strong momentum hasn't quite been ref ...